Concentrated solar power (CSP, also known as “concentrating solar power”) technology uses sunlight directed at heat transfer fluids that heat up and whose thermal energy is then transferred (e.g., for heating) or turned into electrical power (e.g., by use of a turbine generator). CSP systems typically use lenses or reflectors and tracking systems to focus a large area of sunlight into a small beam. The concentrated sunlight is then used as a heat source for a conventional power plant (e.g., a steam driven turbine generator). A wide range of concentrating technologies exists; the most developed are the solar trough, parabolic dish and solar power tower.
Concentrating or concentrated photovoltaic (CPV) systems include photovoltaic cells or other photovoltaic materials that convert the energy within sunlight to electrical energy. Reflective, refractive, or both reflective and refractive elements are used to concentrate sunlight onto the photovoltaic cells or materials. The use of the reflective and/or refractive materials reduce the quantity of the more expensive photovoltaic materials required in the system.
For both CSP and CPV systems, it is important to accurately reflect solar energy on a target. In order for reflectors to maintain reflected solar energy on a target, they must hold their shape, and they must be able to withstand environmental challenges that may change their shape, position, or integrity. More difficulties in meeting these requirements may be encountered for CSP reflectors due to their relatively larger size.
CSP reflectors made of silver-coated glass panels are relatively expensive, heavy (e.g., more than two times heavier than its sheet metal analogs), difficult to handle, and fragile. Such glass panels may not stand up to extreme environments (e.g., high wind speeds, hail, and debris damage). Recent efforts have been made to make thin film systems to replace these glass based mirrors. Film systems are substantially lighter and more resistant to fracture than glass. However, such films alone are not stiff enough to accurately reflect energy on a target. Even film systems including lamination of the film substrate to an aluminum sheet (e.g., 0.025 to 0.13 centimeters thick) typically do not produce reflectors that are stiff enough to handle the extreme environmental conditions described above. Stiffening approaches include reinforcement with perforated panel and tab structures and the use of reinforcing ribs.
Despite the advances in the industry, reliable and cost-effective methods for stiffening or reinforcing reflectors for use in solar technologies are still needed.